Understanding a seed's content or genotype is useful in a variety of agricultural practices from plant genetic engineering to conventional plant breeding. The seed content reveals information that can be employed to produce, select or develop new plants with improved agronomic, horticultural or economic characteristics or traits. Testing seeds or parts of seeds for selected characteristics often requires extraction and analysis of DNA.
Seeds tend to have a natural protection against destructive forces. Maize, cereals, soybeans, rice, soybeans and other beans, melon, pomegranate, sunflower, safflower, iodized poppy, sesame, cardamom, celery, dill, fennel, nutmeg, and plantain along with other vegetable, crop and flower seeds often are very hard. Because of this protection, crushing hard seeds frequently requires significant mechanical force. Applying manual force to crush seed is slow, difficult, and hard on the lab equipment.
Testing seed lots for purity and other seed contents often requires the extraction of DNA from a very large number of single seeds. Therefore there is the need for an efficient system for high-throughput DNA extraction. To extract DNA from seeds, they must first be fragmented. Several fragmentation methods exist seeds can be manually crushed with a mortar and pestle.
Alkaline lysis is a plasmid extraction technique which was invented by Birnboim and Doly: Cells (E. coli) are disrupted in an alkali solution. The high pH not only lyses the cells but also denatures genomic and plasmid DNA. In the next step the solution containing the lysed cells is neutralized, where the small plasmid DNA, which is circular and supercoiled, snaps back to being double-stranded. A large amount of the genomic DNA, however, stays linear and attaches to the cellular debris. During the following centrifugation step most of the genomic DNA is therefore lost in the pellet.
Sodium chloride has been found to decrease water uptake of seeds (Nizam, I. (Sep. 7, 2011), “Effects of salinity stress on water uptake, germination, and early seedling growth of perennial ryegrass,” African Journal of Biotechnology 10(51):10418-10424).
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